Intensive rescue efforts are under way in Pakistan, two days after Saturday's massive earthquake killed 20-thousand people, and injured tens-of-thousands of others. Officials and aid workers say they expect the death toll from the seven-point-six magnitude earthquake to rise.

Most of the deaths from Saturday's killer quake occurred in the Pakistani-controlled portion of Kashmir, where the epicenter was located. The earthquake also wiped out communities in Pakistan's North-West Frontier Province.

Rescuers are struggling through the shattered ruins of dozens of villages and towns worst hit by the earthquake, but in most cases they are searching for bodies, not survivors.

Rescue teams have yet to arrive in some of the hardest hit areas.

Speaking by telephone from the regional capital, Muzaffarabad, resident Abdul Hameed, says people are trapped under debris.

"This building has collapsed. This is my building. Ten-to-15 people are alive [under the debris]. They are crying for [help], and there is nobody," he said.

Rescue workers and authorities are facing difficulties because of blocked roads and bridges, as well as shortage of relief materials.

Television pictures of the quake-devastated areas indicated the massive relief effort required.

The international community has joined the rescue and relief operations undertaken by the Pakistan government. Donor nations rushed doctors, helicopters, food, tents, and sniffer dogs. Aid agencies say that thousands of people are in urgent need of shelter, and up to four-million could be left homeless.

Ambassador to Pakistan Ryan Crocker told reporters in Islamabad that Washington will provide up to $50 million for earthquake relief and reconstruction. He was speaking to reporters at an airport on the arrival of an American transport plane carrying blankets, plastic sheets, and other supplies for 2,500 affected families.

"We have already got relief supplies on the ground. We will have an air bridge effectively coming into Pakistan," he said. "We will be expecting more flights today. Eight U.S military helicopters have just landed. They will be a critical part of these relief efforts."

Pakistani troops have restored road and communication links with some of the hardest-hit areas. But residents still face food and gasoline shortages, and there has been looting in quake-devastated areas of Pakistani Kashmir as people struggle to find supplies.